Study looks at why co-amoxiclav-resistant E coli infections are on the rise

National Institute of Allergy and Infectious Diseases, National Institutes of Health, Flickr creative commons

A study looking at health records in Oxfordshire over nearly 20 years has suggested that measures to improve antibiotic use in GP surgeries might help to combat the spread of difficult-to-treat, antibiotic-resistant E coli infections.

The research, supported by the NIHR Oxford Biomedical Research Centre, used electronic health records in Oxfordshire to study trends in E coli bloodstream infections, urinary tract infections and antibiotic susceptibilities between 1998 and 2016.

The motivation for the study was the fact that E coli had become the leading cause of bloodstream infections in the UK, and a common cause of urinary tract infections. E. coli is becoming harder to treat, as increasingly the bacteria is not being killed by the common antibiotic co-amoxiclav.

Many hospitals and GPs rely on co-amoxiclav treat patients with urine, chest and bloodstream infections.

Difficult to treat

“We wanted to find out whether this was because the infection might be spreading in hospital, or becoming more common in people in the community’,” said one of the authors of the study, Karina-Doris Vihta, of the Nuffield Department of Clinical Medicine.

“We also wanted to look at why the E coli bacteria were becoming more difficult to treat.”

The Infections in Oxfordshire Research Database contains completely anonymised routinely collected electronic health records on admissions and microbiology results in the county across two decades. This allowed the research team to look at trends in the number of E coli bloodstream infections in hospital and outside.

“We showed that the increase in E coli bloodstream infections was coming from patients who had last been admitted to the hospital more than a month before the bloodstream infection. We found that hard-to-treat ‘co-amoxiclav-resistant’ E coli bloodstream infections were increasing at a faster rate than the non-resistant E coli infections,” Vihta said.

No worse

“However despite the laboratory tests showing more of these resistant E coli bacteria were happening over time, patients with bloodstream infections were not doing any worse than before. We found no evidence of increased mortality among these cases.”

The study also found that GP surgeries that prescribed more co-amoxiclav in the previous year were more likely to see more ‘co-amoxiclav-resistant’ E coli urinary tract infections.

“This research suggests that measures to improve antibiotic use in GP surgeries might be effective in preventing resistant E coli bloodstream infections from increasing further, and becoming more difficult to treat,” said Dr Nicola Fawcett, one of the co-authors of the study.

“It also suggests that we don’t need to stop using co-amoxiclav just yet – patients aren’t doing worse despite more resistant bacteria causing infections. Ultimately all healthcare institutions should be focusing on improving antibiotic use and hygiene measures if we want to prevent infections increasing.”